1. Field of the Invention
This invention relates to a parallel flow heat exchanger, and in particular to a heat exchanger having a two-piece header.
2. Description of the Prior Art
Heat exchangers or condensers, such as those used for condensing refrigerant in automobile air conditioning units, have been constructed using a plurality of parallel flow tubes which are connected at each end to manifolds or headers. In one type the headers are generally cylindrical single-piece tubes. The tubes are typically formed by rolling a sheet into a tube configuration and brazing the seam. This type can be manufactured at high production rates, but the tooling required to form these headers is expensive. In another type, the header assembly is formed in two pieces, sometimes referred to as header and tank portions. The two pieces are assembled and brazed together. Generally, it is more difficult to achieve high production rates with the two-piece type, but the tooling is less expensive.
In both types, baffles or fluid partitions located within the headers divert refrigerant through banks of several of the parallel tubes so that the fluid is passed between the headers. By passing the fluid through several banks of the parallel flow tubes, the fluid can be passed over a large amount of surface area within a relatively small amount of space.
Because fluid partitions or baffles used in these condensers are located within the interior of the header, in the two-piece header, the partition is properly positioned before the header portions are joined together. Various techniques are used to retain the partition before the two portions of the header are joined, but improvements are needed.
The parallel flow tubes are normally inserted into slots formed in the header and then the assembly is brazed in a furnace. Often it is difficult to ensure that the flow tubes are inserted into the header the proper distance before brazing.